HLA-A and Behcet disease: When the HLA-B*51-negative patient and control groups were stratified for presence or absence of HLA-A*26, the association of HLA-Bw4-80I with BD still held true in the German patients (see Additional file 1: Table S6) Only a weak association of HLA-Bw4-80I with BD was calculated from a similar regression analysis of the Turkish cohorts.